Thermostatic element



1932- P.- M. LINCOLN 1,890,909

'THERMOSTATIG ELEMENT Filed Aug. 22. 1929 In 1 6 for. Pau/ML/flco/h.

40 escape of steam.

Patented n... is, 1932 UNITED STATES PATENT OFFICE PAUL E LINOOLN, OF ITHCA NEW YORK HERMOSTATIO ELEMENT Application filed August 22, 1929. Serial No. 387,662.

r The principal objects of the invention are to provide a thermostatic element which will be very ation an may be applie to numerous uses. 2 The prinoipalfeature of the invention consists-in the novel use of the expansible quality of soft rubber under an increase of temperature, whereby the rubber is confinedagainst expansion in certain directions but is free to l 'expand in other directions and to exert its expansile movement and force in operating 1 various forms of thermostatically controlled devices. y a a y In the accompanying drawing, Figure 1 1s 15 a diagrammatic sectional view' showing the application of the PIGSGIItdIIVGIItlOIl to an *air control valve for radiators.

Fi re 2'is a diagrammatic plan view show-- ing t e application of this invention to an m electric meter.

' 80 soft rubber none as the thermostatic element,

it being necessary to-confine the soft rubber to permit its expansion to take place in certain definite directions in order to accomplish V the desired result. 7 "85 In the diagrammatic illustration ofthe invention shown in Fi re 1, the invention is applied to an air va ve commonly used on steam radiators, the function of which is to 7 permit the escape 'of air but toprevent'the In the device herein shown, a valve block I 1 which is provided with a threaded plug 2 to be inserted into the wall 3 of a radiator, is a provided with a valve seat 4 at the outer end of an openingo connecting with the interior of the radiator. o i a Attached to the block 1 is a closed tube 6 which is referabl formed of metal and which will e a goo conductor of heat.

60 W .thin the tube 6 is arranged a plug 7 of' positive and de endable in its opersoft rubber. This rubber is fitted snugly into the tube so that it is initially under a slight compression and has secured to one end thereof aplunger 8 to which is secured. a valve 9 adapted to close against the valve seat 4. The plunger thus acts as a piston in the tube.

The plunger8 is movable longitudinally within the cylinder 6 in accordance with the expansion and contraction of the rubber.

Rubber is an extremely elastic material but it is possessed of the peculiar quality of being practically incompressible and it is very susceptible to the influence of changes of temperature. When therefore a body of soft rubber is enclosed and is free to expand'under temperature change in only certain definite directions, the force exerted in such expansion is very positive and stron and when applied to a valve structure'suc as shown and described, theheat from the radiator is conveyed through the metallic block 1 and cylinder 2 to the rubber and the rubber in expanding forces the valve 9 into operating contact with the valve seat 4 to close the same.

The operation of this valve is extremely Sim 'le; When the radiator becomes cool the rub r contracts within its enclosure 6 and drawing the plunger 8 inwardly o ens the valve 9. When steam enters the radlator the air is expelled therefrom through, the opening 5 but upon the temperatureincreasing through the effect of. the steam approaching the air vent, the rubber expands and pressing the plunger outwardly closes the valve.

In the form of application of the invention diagrammatically illustrated in Figures 2 and 3, a pair of cylinders 10 closed at one end are secured to an arm 11 which is pivotally moun'tedat the point 12 on a suitable base 13.

The tubes 10 may be of metal or an other pressure resistingmaterial and within t e bore of thecylinders 10 is placed a plug 14 of soft -rubber,-preferably fitting the bore snugly so that it is under slight tension or compression whereby further expansion toward the confining walls of the tubes-is definitely obviated. It will thus be seen that the total volumetric variations of the rubber in expanding or contracting will be preserved and the resultant movement or displacement of the rubher body will be concentrated at its point of non-confinement and the movement at this point will be of an amplified character since such movement represents the total volumetric expansion or contraction of the mass of rubber. Thus an extremely sensitive action is obtained which will accurately indicate the change in the rubber body in direct proportion to the chan e in temperature of the body. Thus it wil be evident that an increase in the size of the rubber body under confinement with a. iven size of outlet 'or' non-confined area wi 1 effect a proportionate increase or amplification of the movement of the rubber body at such point so that an extremely sensitive condition may be obtained.

' Further, the movement of the body at the point of non-confinement say in the ex ansion riod is very positive and definite. his will i; found extremely desirable, particularly since the tremendous force set up enables the direct application thereof to the operation of means requiring such force, the field of application being thereby greatly increased.

A metal or other plug 15 of a hard nature is slidabl mounted in the open end of each of the c 'nders 10 and it is adapted to slide freely t ereinto follow the ex ansion and contractionmovement of the ru ber.

An arm 16'which is here shown as an indi- 'cator arm is-pivotally secured to the base at a point 17, preferably between the the members 15 of the cylinders 10.

One of the cylinders 10 has a heater coil 18 wrapped therearound. This heater coil is in points of the present instance intended to be connected to a suitable electric circuit and current will flow therethrough and impart a certain heat to the cylinder 10 in roportion to the resistance of the heater so that a' direct relation between the current and the heat generated exists. The heat thus applied to one of the cylinders 10 is imparted to the rubber plug conapplication of the present invention which is extremely simple, ut it mustbe understood that other forms ma be designed and utilized without departing rom the spirit of the invention, which is to utilize the expansionforce of softrubber under changin temperature conditions to operate devices 0 various kinds adapted to be thermostatically controlled.

Where the present invention is desired to be iitilized say as an operative medium functioning at low temperatures, say at freezing or lower, it will beunderstood of course that the initial compression, or tension imparted to the rubber body by reason of its close or snug fit within the confining casing will be such that the body, due to contraction at the lower temperatures, will not entirely lose the initial compression and will at all times'bear against the confining walls of the enclosing tube at a greater or lesser pressure as determined by the temperature changes.

4 What Iclaim as my invention is 1. A thermostatic device, comprising in combination an arm pitvotally mounted at one end, a pair of cylinders open at one end I'lgldl secured to the free end of said arm and space apart, a rubber core inserted in each of 7 said cylinders, a plunger arranged in each of said cylinders and havin pointed ends extending from the open en s of said cylinders, an indicator arm pivotally mounted and engaged on opposite sides of its respective pointed ends of said p ungers,'and

means for difierentially' applying heatto said v:

cylinders.

r 2. A thermostatic device, comprising a pair of soft rubber bodies each separately confined under permanent whereby the'total volumetric ex ansive. effort may be utilized, means for differentially heating saidcompress'ed rubber bodies, and. means for measuring the difference in the total volumetric expansion of said soft rubber bodies.

Will It" W l ivot by the compression for diflerentiallyheatihg said expansible rubber bodies.

5. A thermostatic device as claimed in claim4'in which the weight of said cylinders,

5 rubber bodies and plungers are suspended in a floating manner by enga, exnent of the plunfirs with said arm, the cy inder axes and arm ingdisposed respectively in substan tially vertical and horizontal relation.

PAUL M. LINCOLN. 

